HPV Vaccination: Data at Last

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HPV Vaccination: Data at Last

The short-term results of a three-dose immunization schedule are impressive for many recipients. As for the long term: Still unclear.

The quadrivalent human papillomavirus (HPV) vaccine was released to much fanfare and political wrangling last year based on data from an early analysis of two giant industry-sponsored, blinded, placebo-controlled phase III trials. Updates from these ongoing studies have now been published.

More than 5000 women worldwide (age range, 16–24) were enrolled in the first study; about 27% had prevaccination evidence of genital infection with a vaccine serotype. After a mean follow-up of almost 3 years, the rates of vaccine-type vulvar, vaginal, and perianal lesions (including warts, precancerous lesions, and cancer) were significantly lower among vaccine recipients without evidence of prior infection, as were the rates of cervical intraepithelial neoplasia (CIN) grades 1–3 and cervical adenocarcinoma in situ. An intention-to-treat analysis of all lesions in all subjects found that the vaccine reduced the incidence of vulvar, vaginal, or perianal lesions by 34%, regardless of HPV type, and reduced incidence of cervical lesions by 20%, regardless of HPV type.

A second study focused specifically on high-grade cervical lesions. After a mean 3-year follow-up of more than 12,000 women, the vaccine was 95%–98% protective against grade 2 or 3 CIN or adenocarcinoma in situ associated with vaccine-type HPV among women without prior evidence of infection; among all women, including those with evidence of prior infection, vaccine efficacy was 44%. Side effects were limited to local reactions and a single episode of vaccine-induced bronchospasm.

Comment: The bottom line seems clear: If women are immunized prior to natural infection with pathogenic HPV serotypes, this vaccine effectively protects them from developing precancerous lesions caused by vaccine strains and presumably protects from cancer as well. The duration of vaccine protection is still unknown. Editorialists point out that, given the biological complexity of HPV-associated disease and the charged political overtones of this vaccine, the practical, ethical, legal and financial challenges of incorporating it into clinical practice will be legion.

— Abigail Zuger, MD

Published in Journal Watch General Medicine May 9, 2007

Citation(s):

Garland SM et al. Quadrivalent vaccine against human papillomavirus to prevent anogenital diseases. N Engl J Med 2007 May 10; 356:1928-43.

Original article (Subscription may be required)
Medline abstract (Free)

The FUTURE II Study Group. Quadrivalent vaccine against human papillomavirus to prevent high-grade cervical lesions. N Engl J Med 2007 May 10; 356:1915-27.